Field of the Disclosure
Embodiments of disclosure generally relate to electronic devices and, more particularly, to radio frequency (RF) emission spectrum randomization and targeting nulling for an electronic device.
Description of the Related Art
Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices are also often used in smaller computing systems (such as touch screens integrated in cellular phones).
Radio frequency (RF) emission is a serious consideration in the design and operation of electronic devices, such as proximity sensor devices. A processing system for a proximity sensor device, such as a capacitive sensing device, can include one or more charge pumps. The charge pumps can be used, for example, to supply charge to reservoir capacitors used in a power supply circuit. A charge pump is one primary source of RF emission from a proximity sensor device. RF emission from the proximity sensor device can interfere with other devices near the proximity sensor device.